This application claims the priority right under Paris Convention of Japanese Patent Application No. 186386/2000 filed on Jun. 30, 1999, the entire disclosure of which is incorporated herein by reference.
i) Field of the Invention
The present invention relates to a scrub cleaning method, a scrub cleaning device for scrub-cleaning the main surface, and a manufacturing method of an information recording medium, for example, of an information recording medium glass substrate, a semiconductor wafer, or another disc-shaped substrate using a sponge, a brush or the like.
ii) Description of Related Art In a disc substrate cleaning device described in Japanese Patent Application Laid-Open No. 206705/1997, a plurality of cleaning stations are arranged, a disc substrate (a circular plate having a central hole) is successively moved through the respective cleaning stations by a transfer device (lifting hook), and the disc substrate is scrub-cleaned by a columnar scrub roller.
In the disc substrate cleaning device, when the disc substrate is transferred to the respective cleaning stations, transfer (conveyance among the cleaning stations) is performed by supporting the central hole of each substrate by the lifting hook, a transfer device needs to be separately disposed, and there is a problem that the device is enlarged in scale. Moreover, when the transfer is performed by supporting the central hole by the lifting hook, there is a problem that the central hole is rubbed and dust is possibly generated.
Furthermore, since much time is required for the transfer to the respective cleaning stations, there is a problem that cleaning time for performing a plurality of cleaning processes is lengthened. Specifically, when the transfer is performed by supporting the central hole of each substrate by the lifting hook, much time is required for a series of operations of substrate stopping, central hole supporting (chucking), transferring, and support (chucking) releasing, and the cleaning time is lengthened. Moreover, when much time is required for the transfer, the substrate dries, and a problem arises that dirt cannot easily be removed.
Particularly, in a one-inch substrate for use in a storage device of a cellular phone, digital camera, car navigation system or the like, since the central hole is small, it is very difficult, with respect to precision and cost, to perform the transfer by supporting the central hole by the lifting hook.
To solve the aforementioned problems, according to the present invention, the following constitutions are provided.
(Constitution 1) A scrub cleaning device comprising: two planar scrubbers; means for supporting the two planar scrubbers so that scrub surfaces are disposed opposite to each other; means for rotating the planar scrubber around a rotation shaft vertical to the planar scrubber; and a guide member disposed so that a substrate held between the two opposite scrubbers may be conveyed in the rotation direction of the scrubber,
wherein the substrate held between said two opposite scrubbers is conveyed in the scrubber rotation direction by the rotation of the scrubber, and rotated by a friction force generated by abutment on said guide member, so that the substrate is scrubbed/cleaned.
(Constitution 2) A scrub cleaning device comprising, a scrub pad comprising: two annular plate scrubbers, and a wheel for supporting the inner peripheral surface of the annular plate scrubber and the surface opposite a scrub surface so that the scrub surfaces of said two annular plate scrubbers fit each other, and for rotating the scrubber around the center shaft of the annular plate scrubber; and a guide member disposed opposite to the wheel on the inner peripheral surface side of the annular plate scrubber and disposed along the outer periphery of the scrub pad so that a substrate may be conveyed in the rotation direction of said scrub pad, wherein the substrate held between said two opposite scrubbers is conveyed in the rotation direction of the scrubber between the wheel on the inner peripheral surface side of the annular plate scrubber and the guide member by the rotation of the scrub pad, and rotated by a friction force generated by abutment on said guide member, so that the substrate is scrubbed/cleaned.
(Constitution 3) A scrub cleaning device comprising: a substrate cleaning section, provided with means for moving a scrubber while at least a part of a substrate is held between two opposite scrubbers, and conveying the substrate in the movement direction of the scrubber, and friction generation means, disposed along the conveyance direction of the substrate, for abutting on the conveyed substrate to generate a friction, for conveying and scrubbing/cleaning the substrate when the substrate is conveyed and rotated by a friction force generated by abutment of the substrate on the friction generation means; a substrate inlet section for conveying the substrate into said substrate cleaning section; and a substrate outlet section for conveying the substrate from said substrate cleaning section.
(Constitution 4) A scrub cleaning device comprising: a pair of scrubbers which are rotatably supported by and rotate driven by a rotation driving means; a substrate inlet section for conveying a substrate prior to cleaning into a gap between the pair of scrubbers; a substrate cleaning section for cleaning the substrate transferred from the substrate inlet section with a cleaning liquid supplied from a cleaning liquid supply means; a substrate outlet section for discharging the cleaned substrate transferred from the substrate cleaning section; and a conveyance guiding section for conveying the substrate in cooperation with the scrubbers from the substrate inlet section to the substrate cleaning section, and from the substrate cleaning section to the substrate outlet section, wherein the substrate cleaning section further comprises a resistant force supply means for supplying a resistant force to resist against a force in a conveyance direction provided to the substrate by the scrubbers, so that the substrate is scrubbed/cleaned by a differential peripheral speed between the substrate and the scrubbers generated by the resistant force supply means.
(Constitution 5) The scrub cleaning device according to constitution 3 or 4, wherein a sensor for confirming the presence/absence of the substrate is disposed on at least one of the substrate cleaning section, the substrate introducing section and the substrate discharging section.
(Constitution 6) The scrub cleaning device according to any one of constitutions 1 to 5, further comprising stop means for abutting on the substrate conveyed in the rotation direction of the scrubber to temporarily stop the conveyance of the substrate, and forcibly performing the scrub cleaning of the substrate.
(Constitution 7) The scrub cleaning device according to constitution 6, wherein a sensor for confirming the presence/absence of the substrate is disposed at a position where the conveyance of the substrate is temporarily stopped.
(Constitution 8) A scrub cleaning device comprising: a plurality of cleaning stations comprising the constitution according to any one of constitutions 1 to 7; and a conveyance mechanism for conveying a substrate cleaned in the cleaning station to the next cleaning station in said plurality of cleaning stations.
(Constitution 9) The scrub cleaning device according to constitution 8 wherein said conveyance mechanism comprises a guide member for connecting the scrubbers of said plurality of cleaning stations to one another.
(Constitution 10) The scrub cleaning device according to constitution 8 wherein said conveyance mechanism comprises a guide member for connecting the scrubbers of said plurality of cleaning stations to one another, and a scrub roller for holding the substrate along the guide member from opposite sides and conveying the substrate.
(Constitution 11) The scrub cleaning device according to any one of constitutions 1 to 10, further comprising cleaning liquid supply means for supplying a cleaning liquid to at least one of the scrubber and the substrate held between two scrubbers.
(Constitution 12) The scrub cleaning device according to any one of constitutions 1 to 11, comprising a vertically disposed device for holding the vertically disposed substrate from opposite sides between two vertically disposed scrubbers.
(Constitution 13) The scrub cleaning device according to any one of constitutions 1 to 12 wherein said substrate is a glass substrate for an information recording medium.
(Constitution 14) A scrub cleaning method comprising the steps of: rotating a scrubber while a substrate is held between two opposite planar scrubbers; conveying the substrate in the rotation direction of the scrubber; and generating a peripheral speed difference between the substrate and the scrubber by rotation of the scrubber to perform the scrub cleaning of the substrate.
(Constitution 15) The scrub cleaning method according to constitution 14, further comprising the step of stopping the substrate conveyed by the scrubber in a predetermined position, and performing the scrub cleaning of the substrate.
(Constitution 16) The scrub cleaning method according to constitution 14 or 15, comprising a substrate cleaning section for performing the scrub cleaning of the substrate, a substrate inlet section for introducing the substrate into said substrate cleaning section, and a substrate outlet section for discharging the substrate from said substrate cleaning section, wherein said substrate is conveyed from the substrate inlet section to the substrate cleaning section, and from the substrate cleaning section to the substrate outlet section in this order.
(Constitution 17) The scrub cleaning method according to constitution 16, wherein a sensor for confirming the presence/absence of the substrate is disposed in at least the substrate cleaning section, and the sensor confirms that any substrate is not present in the substrate cleaning section when the plurality of substrates are subjected to the scrub cleaning, and the substrates are then conveyed from the substrate inlet section to the substrate cleaning section.
(Constitution 18) A manufacturing method of an information recording medium which comprises the steps of subjecting a substrate for an information recording medium to scrub cleaning, and then forming at least a recording layer on the substrate, wherein the scrub cleaning method described in any one of constitutions 14 to 17 is carried out.
In the scrub cleaning method and device of the present invention, the scrubber for performing the scrub cleaning has a function of conveying the substrate to respective cleaning points, the conveyance and transfer of the substrate are smoothly performed, time for transfer to the next cleaning station is shortened, and cleaning time is reduced.
In the present invention, in the device a sensor for detecting the substrate is disposed, and substrate flow can be controlled and managed. For example, as shown in FIG. 8, the container cassette 61, a cleaning point 101 of the first cleaning station, a cleaning point 201 of the second cleaning station and the container cassette 63 are provided with substrate detecting sensors 71, 72, 73, 74, respectively, so that the substrate flow can be controlled and managed. In FIG. 8, the sensor 71 confirms the presence/absence of the substrate 1 in a substrate discharge position in the container cassette 61. The sensor 72 confirms the presence/absence of the substrate 1 in the cleaning point 101 of the first cleaning station. The sensor 73 confirms the presence/absence of the substrate 1 in the cleaning point 201 of the second cleaning station. The sensor 74 confirms the presence/absence of the substrate 1 in the substrate storage position in the container cassette 63. In the container cassette 61, after the-sensor 71 confirms that the substrate 1 exists in the substrate discharge position, and the sensor 72 further confirms that the substrate 1 is absent in the cleaning point 101 of the first cleaning station, the substrate 1 is conveyed to the space between the constantly rotating sponge pieces 11 and 11xe2x80x2 (not shown) of the scrub pad 10. When the sensor 71 confirms that the substrate 1 is absent in the substrate discharge position, the cassette is moved to the next substrate discharge position. In the cleaning point 101 of the first cleaning station, the substrate 1 reaches the position of the free roller 31, the sensor 72 confirms the presence of the substrate 1, then a timer operates and the cleaning is performed in the cleaning point 101 for a fixed time. After it is confirmed that a timer set time elapses (time-up), and the sensor 73 further confirms that no substrate 1 exists in the cleaning point 201 of the second cleaning station, the free roller 31 is retracted and the substrate 1 is passed. When the substrate is passed, the free roller 31 is immediately lowered to its original position. In the cleaning point 201 of the second cleaning station, when the substrate 1 reaches the position of the free roller 31 and the sensor 73 confirms the presence of the substrate 1, the timer operates and the cleaning is performed in the cleaning point 201 for the fixed time. After it is confirmed that the timer set time elapses (time-up), and the sensor 74 further confirms that no substrate 1 exists in the substrate storage position in the container cassette 63, the free roller 31 is retracted and the substrate 1 is passed. When the substrate is passed, the free roller 31 is immediately lowered to its original position. In the container cassette 63, when the sensor 74 confirms that the substrate 1 exists in the substrate storage position, the cassette is moved to the next substrate storage position. In this manner, by passing the substrate after it is confirmed that no substrate exists in the prior process position, a trouble can be prevented from being caused by collision of the substrate.
Additionally, preferably employed is a system which comprises: confirming by the sensor and timer mechanism that the substrate fails to reach the corresponding position even when time required for a series of processes from the discharging to the storing of the substrate elapses, or confirming by the respective sensors and timer mechanism that a predetermined operation time in each sensor position elapses, notifying troubles such as the catching and dropping of the substrate by a buzzer or the like, or stopping the device.
The position and number of the sensors are not limited to the form shown in the drawing, and can appropriately be set. The sensor type is not limited as long as the substrate can be detected, and for example, a sensor for detecting the substrate by reflection of laser beams can be used.
It goes without saying that the respective operations can be performed only by time management without disposing any sensor.
A concrete example of a flowchart showing the above-described substrate flow control is shown in FIG. 9. In FIG. 9, when a start switch is turned on, first as confirmation of an initial state, it is checked (1) whether the cassette 61 for containing the substrate to be cleaned and the empty cassette 63 are exactly installed in predetermined positions (not shown), (2) whether the scrub pad 10 (hereinafter referred to as wheel 1) of the first cleaning station and the scrub pad 10 (hereinafter referred to as wheel 2) of the second cleaning station rotate (not shown), (3) whether the sensor 71 confirms the presence of the substrate and the sensors 72, 73, 74 confirm the absence of the substrate, and (4) whether the free roller 31 (hereinafter referred to as stopper 1) of the first cleaning station and the free roller 31 (hereinafter referred to as stopper 2) of the second cleaning station are lowered. When even one condition is not satisfied, an alarm buzzer is turned on, and an alarm is issued.
After confirmation of the initial state, in the loading mechanism, a hand member raising switch is turned on, and on confirmation of the raising of the hand member, a hand member lowering switch is turned on. When the lowering of the hand member is confirmed, and the sensor 72 confirms the presence of the substrate, the cassette 61 is fed by one pitch. Thereafter, the process returns to the confirming of the presence of the substrate by the sensor 71, and the confirming of the absence of the substrate by the sensor 72, and the same process is repeated.
In the first cleaning station, after the initial state is confirmed, on confirmation of the presence of the substrate by the sensor 72, the timer 1 starts and the cleaning liquid is supplied until the time is up. After the sensor 73 confirms the absence of the substrate, and the lowering of the stopper 2 is confirmed, a raising switch of stopper 1 is turned on. When the sensor 73 confirms the presence of the substrate, a lowering switch of stopper 1 is turned on. Thereafter, the process returns to the confirming of the presence of the substrate by the sensor 72, and the same process is repeated.
In the second cleaning station, after the initial state is confirmed, and the sensor 73 then confirms the presence of the substrate, the timer 2 starts and pure water is supplied to perform rinsing until the time is up. After the sensor 74 confirms the absence of the substrate, a raising switch of stopper 2 is turned on. When the sensor 74 confirms the presence of the substrate, a lowering switch of stopper 2 is turned on. Thereafter, the process returns to the confirming of the presence of the substrate by the sensor 73, and the same process is repeated.
In the unloading mechanism, after the initial state is confirmed, the raising of the stopper 2 is confirmed, and the sensor 74 then confirms the presence of the substrate, the cassette 63 is fed by one pitch. Thereafter, the process returns to the confirming of the absence of the substrate by the sensor 74, and the same process is repeated.
Additionally, when the respective judgment results are xe2x80x9cNoxe2x80x9d, the alarm buzzer is turned on and the alarm is issued. Moreover, FIG. 9 shows one example of the flowchart, and can appropriately be changed. For example, instead of the sensors 72, 73, a sensor for confirming the presence of the substrate in the respective wheels 1 and 2 can be disposed. Moreover, the process can be designed so that on confirmation of the raising of the hand member, the timer 1 is started and the cleaning liquid is supplied until the time is up. The process can also be designed so that similarly on confirmation of the raising of the stopper 1, the timer 2 is started and pure water is supplied until the time is up.
Furthermore, the disc substrate can be conveyed without supporting the central hole, and hence there is not any fear that the central hole is not worn to form dust, so that the generation of a thermal asperity due to the formation of the dust from the central hole can be prevented, whereby the information recording medium (e.g., a magnetic disc) having a high reliability can be manufactured.
In the present invention, the substrate held between two scrubbers is conveyed in the rotation direction by rotation of the scrubber, the peripheral speed difference is generated between the substrate and the scrubber by the friction force generated by abutment of the substrate on the guide member, and the substrate and scrubber rub each other to perform the scrub cleaning.
In order to generate the friction force between the substrate and the guide member, that is, to generate the peripheral speed difference between the substrate and the scrubber, there is provided the stop means (inhibition means) for abutting on the substrate conveyed in the rotation direction of the scrubber to temporarily stop the conveyance of the substrate (e.g., a rotatable free roller), or the holding amount (substrate holding pressure) of the substrate by the scrubber is adjusted. In the latter case, since the substrate rotates during conveyance, the conveying and the scrub cleaning of the substrate are simultaneously performed.
According to the present invention, since it is unnecessary to dispose a large-scaled device for supporting each of the respective substrates and conveying or transferring the substrate to the cleaning point or the next cleaning station, the device can be simplified and miniaturized, and the space can be saved. Particularly, with the vertically disposed device in which the vertically disposed substrate is held from opposite sides between two vertically disposed scrubbers, the space can further be saved.
According to the present invention, there is no fear of dust generation by the rubbing of the central hole, or there is no possibility that the substrate dries or dirt cannot easily be removed.
In the present invention, by disposing the cleaning liquid supply means for supplying the cleaning liquid at least one or preferably both of the scrubber, and the substrate held between two scrubbers, during the cleaning or conveyance, the substrate preferably fails to dry. It is further preferable to also provide the transfer mechanism between the cleaning stations with the supply means of the cleaning liquid (including water).
In the present invention, by disposing the stop means for forcibly performing the scrub cleaning of the substrate, the cleanliness of the substrate is preferably satisfactory.
For the scrub cleaning method and device of the present invention, even when a plurality of cleaning processes are performed, the cleaning time is short, and it is unnecessary to dispose the large-scaled transfer device, which is useful particularly for performing a plurality of cleaning processes.
As the substrate to be cleaned according to the present invention, disc-shaped substrates such as an information recording medium substrate are exemplified. The present invention is suitable particularly for a one-inch substrate, and other substrates difficult to transfer or clean because of the small size.